Major major limiting factor for the rate of photosynthesis under the natural environmental conditions is

Options

A. Temperature
B. Light
C. CO_2 concentration
D. Water

Answer

To determine the major limiting factor for the rate of photosynthesis under natural environmental conditions, we can analyze each of the given options: temperature, light, carbon dioxide concentration, and water.

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose, using carbon dioxide and water.

2. **Identifying Limiting Factors**:
- A limiting factor is a condition that can restrict the rate of a process, in this case, photosynthesis.

3. **Analyzing Each Option**:
- **Temperature**:
- Enzymes play a crucial role in photosynthesis. They are sensitive to temperature changes.
- At low temperatures, enzyme activity decreases, leading to a reduced rate of photosynthesis.
- At high temperatures, enzymes can become denatured, losing their functional shape and thus their ability to catalyze reactions effectively.

- **Light**:
- Light intensity affects the rate of photosynthesis. However, it usually becomes a limiting factor only when light levels are low.

- **Carbon Dioxide Concentration**:
- Carbon dioxide is essential for photosynthesis, and its concentration can limit the process. However, in many natural environments, CO2 levels are often sufficient.

- **Water**:
- Water is necessary for photosynthesis, but plants have adaptations to conserve water, and in many environments, water is not the primary limiting factor.

4. **Conclusion**:
- After analyzing all the options, temperature emerges as the most significant limiting factor for photosynthesis under natural conditions. This is due to its direct impact on enzyme activity, which is crucial for the photosynthetic process.

### Final Answer:
The major limiting factor for the rate of photosynthesis under natural environmental conditions is **temperature**.